Device for vacuum coating

ABSTRACT

A device for vacuum coating comprises a vessel which is adapted to be evacuated and a structure therein which includes a rotary holding structure upon which is mounted a plurality of supporting plates. The supporting plates are mounted for rotation about an axis parallel to the plate surface. The rotary holding structure is driven by a drive ring which during the initial portion of its rotation is effective to rotate the plates to a position at which they will be oriented in a coating position and thereafter to rotate the whole holding ring structure with the plates. The apparatus advantageously includes means for the electronic sputtering within the vessel to generate ionized gases carrying the coating substance and/or means are provided for evaporating substances to produce the coating material.

United States Patent [1 1 Bellmann Mar. 26, 1974 [5 DEVICE FOR VACUUMCOATING 3.396.696 8/1968 Becker 118/49 [75] Inventor: Otto Bellmann,Furstentum,

Liechtenstein Przmary Examiner-Morris Kaplan Attorney, Agent, orFirm-McGlew and Tuttle [73} Assignee: Balzers Patent-undBeteiligungs-Aktiengesellschalt, 57 ABSTRACT Balzers, Liechtenstein Adevice for vacuum coating comprises a vessel WhlCh [22] Filed: Mar. 8,1973 is adapted to be evacuated and a structure therein Appl. No.:339,074

which includes a rotary holding structure upon which is mounted aplurality of supporting plates. The supporting plates are mounted forrotation about an axis parallel to the plate surface. The rotary holdingstructure is driven by a drive ring which during the initial portion ofits rotation is effective to rotate the plates to a position at whichthey will be oriented in a coating position and thereafter to rotate thewhole holding ring structure with the plates. The apparatusadvantageously includes means for the electronic sputtering within thevessel to generate ionized gases carrying the coating substance and/ormeans are provided for evaporating substances to produce the coatingmaterial.

8 Claims, 3 Drawing Figures DEVICE FOR VACUUM COATING BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates in general tovacuum coating devices and in particular to a new and useful vacuumcoating device in which materials to be coated are arranged within achamber which may be evacuated and which includes a rotary structurecarrying a plurality of support plates with means for rotating theplates into a position in which the articles thereon are exposed forevaporation coating and for thereafter rotating them with the rotatablestructure.

2. Description of the Prior Art The present invention relates inparticular to devices for vacuum coating which comprises a vessel whichis evacuated and which holds articles to be coated while they aresubjected to evaporation or cathode sputtering apparatus. In devices ofthis kind it is known to provide a rotary support for moving thearticles which are to be coated and generally such supports are designedas rotatable cages. The rotation is carried out in order to produce amore uniform coating. There are also known holding structures whichcomprise supporting plates which may be inverted so that the objects tobe coated can be turned over without interrupting the vacuum within thevessel. This possibility is advantageous because both sides of thesupporting plates may be used as holding surfaces for the objects forexample such as lenses which may be fixed in recesses of the supportingplate and which therefore may be coated on both sides in one operation.Such an arrangement permits the more economical use of the devices.Devices which are capable of holding the articles to be coated and forinverting them without opening the evacuated vessel are known. Deviceswhich include both rotary motion and movement for the turning over ofthe plates which carry the objects it is usual to employ separatedriving mechanisms for both types of movement and consequently in mostcases two separate sealed bushings must be provided for thetransmissions in each case. Some of the known devices however requirevery large space owing to their complicated transmission mecha nism andtherefore they are not suitable for most installations and they are verysusceptible to disturbances.

SUMMARY OF THE INVENTION The present invention provides a device forsupporting articles which are to be coated in an evacuated chamber andwhich includes a simple means for both inverting the article and forrotating it during the coating process. The device includes a rotaryholding structure arranged within a vessel which may be evacuated andwhich includes a plurality of supporting plates for the objects to becoated. Appropriate devices for coating the objects such as anevaporation or cathode sputtering equipment are provided in the vessel.A drive mechanism drives the holding structure to produce rotary motionof the objects to be coated during the coating process and the movementis preferably about a vertical axis. The drive mechanism also includesmeans permitting the turning of the supporting plates to bring them intoselected coating positions which is advantageously carried out prior tothe rotary movement of the plates. The construction includes a drivering which is provided with rotatable shaft elements which drive theplates to rotate them for arranging the plate surfaces in a propercoating position after subsequently fixing the drive ring in respect tothe holding structure so that continued rotation of the drive ringcauses rotation of the holding structure.

Accordingly it is an object of the invention to provide an improveddevice for holding objects to be coated in an evacuation plant whichincludes a support structure including a rotatable holding structurehaving at least one plate thereon and drive means connected to saidholding structure and to said plate for rotating said plate to positionsaid plate in a desired coating position and thereafter to rotate saidholding structure to rotate the plate while it is held in the coatingposition.

A further object of the invention is to provide an apparatus for coatingarticles in a reduced pressure atmosphere within a vessel which includesmeans for both rotating and inverting the position of articles to becoated arranged within the vessel.

A further object of the invention is to provide a coating device whichis simple in design, rugged in construction and economical tomanufacture.

For an understanding of the principles of the invention, reference ismade to the following description of typical embodiment thereof asillustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing:

FIG. 1 is a transverse sectional view of a vacuum coating apparatusconstructed in accordance with the invention;

FIG. 2 is a section taken along the line AA of FIG. 1; and

FIG. 3 is a section taken along the line 8-8 of FIG. 2.

GENERAL DESCRIPTION OF THE PREFERRED v EMBODIMENT Referring to thedrawings in particular, the invention embodied therein comprises avacuum coating unit which comprises a vessel generally designated 50having a bottom or base portion 1 and a double walled bell or topportion 2.

In accordance with the invention a device generally designated 52 forsupporting objects to be coated so that they may be rotated during thecoating process and so that they may be changed in position for exampleinverted for subsequent coating, is mounted within the bell 2 over thebase 1. The holding dstructure 52 includes a base ring 5 which ismounted so as to be rotated by individual rollers 4 which are arrangedto rotate the ring 5 about a vertical axis 3. A first cage portion ofthe structure 52 includes the ring 5 which has upright rods 6 thereonwhich support a top structure generally designated 8. The top structure8 includes an inner ring 9 and an outer ring 10. A plurality of radiallyextending arms arranged around the circumference interconnect the tworings 9 and 10. In accordance with a feature of the invention supportingplates 11 for carrying objects to be coated or moutned for rotationabout an axis extending parallel to the plane of the plate on journals54 which are rotatably supported on the-inner plate 9 and journals 56which are rotatably supported on the outer plate 10. The journal 56carries a small gear 13 which rides in meshing engagement with a rack 15which is carried on a ring 14 ofa second rotary cage construction. Theupper drive ring is also rotatable about the axis 3 and it is supportedon vertically extending rods 17 which are carried on a lower drive ring16. Thus, a first rotary cage structure which includes the drive ring 5,the vertically extending rod 6 and the inner and outer rings 9 and 10which are supported on brackets 7 on the rod 6 may be rotated separatelyby the drive rollers 4 or it may be rotated after rotation of a secondrotary cage assembly which includes the lower drive ring 16, thevertical rod 17 and the upper ring 14 which carries the rack 15. Whenthe first rotatable cage rotates in respect to the second rotatable cagethe gear 13 moves on the rack to cause rotation of the individual plates11 and this movement may continue until the two rotary cages are coupledtogether at which time the plates 11 will move into a postion in whichthey hold the articles at a proper position for coating. Thus for thecoating process the objects to be coated are fixed to the supportingplate 11 forexample by means of clamps or screws (not shown).

The special equipment for the coating itself particularly theevaporation source as well as devices for the cathode sputtering or forproducing layers in an electric glow discharge for example in anatmosphere of an organic or inorgainic vapor, is only schematicallyindicated at 27. Such equipment is well known however and does not forman essential part of the invention.

The rods 6 of the first rotary cage pass through arcshaped oblong slots18 of the lower drive ring 16 of the second rotary cage. The slots 18are of such a dimension that a relative movement between the two cagesmay take place to permit the gear 13 to run over the rack 14 and causerotation or turning over of the supporting plates 11.

In the embodiment shown the drive ring 16 is driven by a drive roller 2]which is in frictional engagement therewith and which in turn is drivenby a motor 22 through a V-belt transmission 23 which is connectedthrough a sealed bushing 24 in the bottom 1. During the initial movementof the ring 16 the plates 11 are turned until they are oriented in adesired position for coating and this may be determined when they abutagainst a stop which defines the coating position. If rotation proceedsin an opposite direction the supporting plates are rotated in anopposite direction until they are stopped in a second coating position.The stops advantageously comprise connecting arms 25 and the plates areadvantageously constructed so that they hit the arms in each endposition. in some cases it is desirable to provide additional stops onthe top structure 8 and to make them adjustable to define predeterminedcoating positions of the plates 11. The slots 18 are advantageouslydimensioned so that the rods 6 abut at the ends 19 or 20 at the endpositions of rotatable movement of the plates 11.

The operation of the device is as folllows:

After the objects to be coated have been fixed to the supporting plates11 and the coating equipment prepared for service, the bell 2 is closedand the vessel is evacuated down to the operation pressure. The secondrotary cage which includes the bottom ring 16 the rods 17 and the upperring 14 is driven by the motor 22 and during the initial stages of itsrotation it turns the supporting plates 11 by driving through the rack15 and the gear 13. The movement continues until the coating position ofthe plates 11 is attained as determined by the location at which it hitsa stop. When this occurs no further relative motion is possible betweenthe first and second rotary cages so that the first rotary cage bearingthe top structure 8 is driven along with the second rotary cage and thewhole structure including the supporting plates 11 which are held withina coating position is continuously rotated. During this time the coatingon one side of the supporting plates 11 is carried out. As soon as thecoating of this side of the objects is finished the rotation is reversedfor example by reversing the motor 22 and during this initial portion ofreverse rotary movement the support plates 11 are again turned over to asecond coating position. After they reach the second coating positionthe whole structure then rotates together during the next coatingoperation.

It is also possible to use a base ring 5 instead of the drive ring 16 asthe driving mechanism since it is only the relative motion between thetwo cages that determines the rotatable movement of the article supportplates 11. In such a casein the beginning of rotation first the onecoating position corresponding to this rotational direction is adjustedand after attaining this position the top structure is then put intorotation. When the ring 5 is driven in the opposite direction first thesupporting plates are brought into their second coating position andthereupon the whole structure turns together.

As is easily seen from the drawings instead of using whole rotary cagesit is possible to establish the same motion transmission through tworotatable ring structures which rotate about a common axis and with oneof them carrying the top structure and the other being capable ofexecuting a limited movement in respect to the one carrying the topstructure. These rings may be supported and rotatably mounted on theinner surface of the bell 2 instead of being supported by means of therod 6 or 17 and the rings 5 or 16 shown in FIG. 1. As is shown in FIG. 1in dashed lines the ring could also be driven by means of a transmissionincluding the drive shaft 28 from a connection through the bell at thetop thereof.

FIG. 3 indicates the mounting of the rings 5 and 16 so that they can berotated relative to each other about the common axis 3. The rings aresupported on ball bearings 26.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:

l. A device for vacuum coating, comprising a vessel adapted to beevacuated, a holding structure arranged within said vessel having anouter periphery orbital about a central axis, a supporting plate for theobjects to be coated mounted on the outer periphery of said holdingstructure and being rotatable about an axis of said plate, means in saidvessel for coating the objects, drive means operable during the coatingprocess to put said holding structure into orbital motion and initiallyto invert the supporting plate about said axis of said plate thereby tobring it into a coating position and said drive means further includingmeans to thereafter stop plate movement about said plate axis and, tohold it in said coating position during further orbiting of said holdingstructure and said support plate.

2. A device according to claim 1 wherein said means to invert thesupporting plate and to stop movement about the plate axis includes adrive ring connected to rotate said plate to turn them and couplingmeans coupling said drive ring to said rotatable holding structure tosimultaneously rotate said drive ring and said holding structure and tostop turning said supporting plate.

3. A device according to claim 2 wherein said holding structurecomprises a rotary cage including at least one said supporting platewhich is rotatable thereon and adapted to be rotated 180.

4. A device according to claim 1 wherein said drive means comprises anorbital cage, said holding structure including inner and outer platesupport rings, said plates being journalled for rotation in said platesupport rings.

5. A device according to claim 1 wherein said holding structure and saiddrive means comprise separate orbital cages interengaged andconcentrically arranged each having vertically extending rods and onehaving a drive ring with an elongated arcuate slot therethrough throughwhich the rods of the other extend.

6. A device according to claim 5 wherein said drive ring has a toothedrim said plates having a gear affixed to the axis thereof which isengaged with the toothed rim of said drive ring.

7. A device for vacuum coating comprising a vessel having a base portionand a bell portion covering said base portion, said vessel being adaptedto be evacuated to reduce the pressure therein, means in said vessel forcoating objects, a first structure orbital about a central axis andhaving at least one article receiving plate thereon for articles to becoated, means on said holding structure for mounting said plates forrotation about an axis extending at an angle to the orbit axis, a secondorbital structure connected to said first strucure, drive gear meansdefined between said first and second orbital structures to rotate saidplate upon relative rotation of said first and second orbital structuresand coupling means coupling said first and second orbital structurestogether for orbiting together and permitting initial independentorbital movement of said first structure relative to said secondstructure for driving said plates to a rotated position at which theywill be disposed during the coating process and which is thereaftereffective to orbit both said structures together to hold said plate in acoating postion during the coating process.

8. An apparatus according to claim 7 wherein said drive means includes afirst drive ring connected to said first structure, and motor meansconnected to said drive ring to rotate said drive ring, said couplingmeans including a ring on said second structure having an elongatedarcuate slot and a rod on said first drive ring extending through saidslot and permitting relative movement between said first drive ring andsaid second drive ring to the end of travel of said slot and thencombined movement of said drive means thereafter.

1. A device for vacuum coating, comprising a vessel adapted to be evacuated, a holding structure arranged within said vessel having an outer periphery orbital about a central axis, a supporting plate for the objects to be coated mounted on the outer periphery of said holding structure and being rotatable about an axis of said plate, means in said vessel for coating the objects, drive means operable during the coating process to put said holding structure into orbital motion and initially to invert the supporting plate about said axis of said plate thereby to bring it into a coating position and said drive means further including means to thereafter stop plate movement about said plate axis and, to hold it in said coating position during further orbiting of said holding structure and said support plate.
 2. A device according to claim 1 wherein said means to invert the supporting plate and to stop movement about the plate axis includes a drive ring connected to rotate said plate to turn them and coupling means coupling said drive ring to said rotatable holding structure to simultaneously rotate said drive ring and said holding structure and to stop turning said supporting plate.
 3. A device according to claim 2 wherein said holding structure comprises a rotary cage including at least one said supporting plate which is rotatable thereon and adapted to be rotated 180*.
 4. A device according to claim 1 wherein said drive means comprises an orbital cage, said holding structure including inner and outer plate support rings, said plates being journalled for rotation in said plate support rings.
 5. A device according to claim 1 wherein said holding structure and said drive means comprise separate orbital cages interengaged and concentrically arranged each having vertically extending rods and one having a drive ring with an elongated arcuate slot therethrough through which the rods of the other extend.
 6. A device according to claim 5 wherein said drive ring has a toothed rim said plates having a gear affixed to the axis thereof which is engaged with tHe toothed rim of said drive ring.
 7. A device for vacuum coating comprising a vessel having a base portion and a bell portion covering said base portion, said vessel being adapted to be evacuated to reduce the pressure therein, means in said vessel for coating objects, a first structure orbital about a central axis and having at least one article receiving plate thereon for articles to be coated, means on said holding structure for mounting said plates for rotation about an axis extending at an angle to the orbit axis, a second orbital structure connected to said first strucure, drive gear means defined between said first and second orbital structures to rotate said plate upon relative rotation of said first and second orbital structures and coupling means coupling said first and second orbital structures together for orbiting together and permitting initial independent orbital movement of said first structure relative to said second structure for driving said plates to a rotated position at which they will be disposed during the coating process and which is thereafter effective to orbit both said structures together to hold said plate in a coating postion during the coating process.
 8. An apparatus according to claim 7 wherein said drive means includes a first drive ring connected to said first structure, and motor means connected to said drive ring to rotate said drive ring, said coupling means including a ring on said second structure having an elongated arcuate slot and a rod on said first drive ring extending through said slot and permitting relative movement between said first drive ring and said second drive ring to the end of travel of said slot and then combined movement of said drive means thereafter. 